The present invention relates to a display apparatus that projects vibrating beams of light onto an object to form a video image thereon.
Conventional projection devices use a projection lens to project a video onto an object such as a screen or the like.
Under these circumstances, a display apparatus using MEMS (Micro Electro Mechanical Systems) devices and laser beams has come to be known and is disclosed in JP-A-2006-343397 (page 10, FIG. 1).
There have been proposed many kinds of measuring methods and devices. Among the methods using beams a light pulse flight hour measuring method is known. With both advancement of technologies in such MEMS field, semiconductor laser field or the like and reductions in product size or cost in recent years, these methods are being considered for application not only to business use but also to home use.
For example, a technology for improving a measuring precision is introduced in an article “OMRON TECHNICS, Vol. 44, No. 1 (145 issue) 2004”. A distance image sensor operable based on the light pulse flight hour measuring method using MEMS and laser beams is also introduced at http://www.signal.co.jp/vbc/mems/app/item01—1.html (Nippon Shingo K.K).
As disclosed in JP-A-2006-343397 (page 10, FIG. 1), it has become possible to construct an image display apparatus which uses a uni-axial or dual-axial MEMS mirror reciprocally vibrating, or rocking and which projects a beam having been reflected at the MEMS mirror onto an object to form an image thereon.
Because the semiconductor technology advancement in recent years has improved an amount of output energy of a laser beam source and an electro-optical conversion efficiency, and also has improved a selectivity of an oscillated wavelength in a visible range, the image display apparatus is being improved more easily in a color reproducing range and a brightness range at low cost.
Since a projected light or image is formed as a beam, the image display apparatus is then able to produce, by beam projection, a focused image at any distance on an object of not only a flat shape but also various undulated contours.
However, when an image is actually projected onto the undulated or uneven surface of an object, the projected image on the object may get distorted because of differences of degrees of such undulation or unevenness over the recessed and protruding surfaces of the object. This is caused by the fact that the projected video is displayed enlarged in proportion to the projection distance.
The above-described display apparatus is simple in construction and thus can be made small, so that it can be brought in any desired place where it is used for projection display. Therefore, an object on which a projected image is displayed may be formed in a variety of shapes in addition to undulated contours, with its surface given a variety colors and glossiness levels of surface.
An object of this invention is to provide a display apparatus which, when projecting and displaying a video on a curved surface, realizes a displaying of an undistorted video by detecting the curved surface contour with high precision and unevenly rearranging (reverse-correcting distortions of) pixels of the image being displayed according to the detected curved surface contour (distortion), thereby widening the forms of use, and improving convenience of use, of the display apparatus.